Parmitano set out first. Initially, he recalls, “it was okay.” He traveled the same path he’d used to exit the station, following his tether around the Z1 Truss, moving from one handrail to the next. Halfway back to the airlock, he came to a protruding antenna boom he had to maneuver around. On every EVA, astronauts are given a list of items to avoid touching. It might be a fragile or hazardous piece of equipment, or a panel with a delicate coating. Even certain handrails are off-limits: those with sharp pits from meteoroid impacts, which, like freshly cut metal, could rip the spacewalkers’ gloves. The antenna was on the list. To navigate around it, Parmitano says, “I had to flip up with my head toward the station and my feet toward the sky.”That’s when things got bad. Whether it was the flipping motion or just his Snoopy cap becoming so saturated that the water had nowhere else to flow, a large blob of liquid moved down, covering Parmitano’s eyes and getting in his nostrils. Now he could breathe only through his mouth, and he couldn’t see clearly through the glob of liquid clinging to his face.

Then the sun went down.

Ordinarily this was no problem—his helmet had a headlight. But in space, with no air to refract the beam, the light illuminated only a small, tight circle directly in front of him. The rest was utter darkness. It was hard enough to tell one handrail from another under normal circumstances. With the water glob, it was almost impossible. He started to realize his Snoopy cap had stopped working, and that nobody could hear him anymore. Since the spacewalk, friends have complimented him for his stoic silence during this time. “I’ve been told that I was cool as a cucumber,” he says. “The truth is that I was trying to talk.”

Even though he couldn’t see, he called on his knowledge of the station’s architecture to get his bearings, and could feel the tug of the spring-loaded tether, telling him he was moving in the right direction. Finally he saw the hatch cover, and light inside. “I’m at the airlock,” he radioed to the ground—a sudden burst of good comm. He floated head-first through the outer hatch. He was back.

***

Inside the station, Karen Nyberg had heard the call to terminate and immediately went to get her Russian crewmates—Pavel Vinogradov, Fyodor Yurchikhin, and Sasha Misurkin. Ordinarily just one of the Russians would have been on hand to help bring U.S. spacewalkers inside, but all of them pitched in, rounding up towels and offering Nyberg help. They were in an equipment room attached to the tiny outer airlock, and could see Parmitano through a little porthole, although they couldn’t see his face.

Cassidy’s anxiety had been building in the several minutes it took him to get back to the hatch himself. He hadn’t heard anything from Parmitano, and when he did finally hear “I’m at the airlock” over the loop, it was followed by some scratchy half-sentence about “a lot of water.”

In order to get Parmitano back inside the station with his helmet off, Cassidy would have to close the outer hatch, followed by several minutes of repressurizing the airlock before they could open the inner hatch to the room where Nyberg and the Russians were waiting.

Ever since the water had covered his nose, Parmitano had been working out a plan in his head. If it moved to his mouth and he could no longer breathe, he would open a purge valve in his helmet to try to let some of the liquid out. As a last-ditch effort, he could even open the helmet. He’d probably pass out, but at least he wouldn’t drown. But that worked only if the airlock were closed. Cassidy had something similar in mind as he struggled with the bulky outer door. “That was my most important job,” he says. “I had the rest of Luca’s life to get the hatch closed.”

The instant he did, Nyberg turned the valve to start repressurizing the airlock. Now it was just a matter of waiting several minutes while it filled with air and the astronauts adjusted to the change in pressure. Still unable to communicate, Parmitano says he “was just waiting for the [repressurization] to end, taking it one second at a time. At that point I’m virtually isolated from a sensory point of view. I can’t hear. I can’t really see. I can’t move. Every time I moved, the water sloshed around.” So he kept as still as possible, trying to keep it from reaching his mouth.